Leonardo Da Vinci

by Charles Nicholl

  The wildest area he describes in these notes is the ‘Chiavenna valley’ – in other words the valley of the Mera river, which flows down from Mount Chiavenna to debouch into Lake Como. The mountain is right up against the border with Switzerland: not far across the border is St Moritz.

  In the Chiavenna valley… are very high barren mountains with huge rocks. Among these mountains you see the water-birds called marangoni [cormorants, but this seems unlikely; perhaps wild geese]. Here grow firs, larches and pines. There are deer, wild goats, chamois and terrible bears. It is impossible to climb up without going on hands and feet. The peasants go there at the time of the snows with huge devices to make the bears tumble down the slopes.

  This is very vivid – scrabbling up the precipitous slopes; birds flying up from the pine woods. And those ‘terrible bears’ trapped by the locals with devices that make them ‘traboccare giù’ – a dynamic verb: literally, ‘to overflow’ or ‘spill over’; thus to fall face downward, as for instance into a hunter’s pit or trabocchetto. The device is perhaps a system of trip-wires.

  There is a drawing by Leonardo of a head of a bear, and another that is usually said to show a bear walking, though in neither case can one say for sure that the bear is alive.47 The ‘walking’ animal could as easily be a dead bear suitably propped up, as in countless ‘big-game hunter’ photos; the extruded tongue and the turned-up eye in fact suggest this. A series of anatomical studies at Windsor, once unhelpfully catalogued as showing ‘the foot of a monster’ but since 1919 identified as the hind-leg of a bear, also belongs to this time.48 Leonardo did not need to go into the Alps in order to see a bear – there were plenty brought into the city: live bears for performance; dead bears for fur – but it seems likely that these drawings are connected with his experience of bear-hunting in the Chiavenna valley in the early 1490s.

  Another Alpine expedition took him even higher, for in a note which argues that ‘the blue we see in the air is not an intrinsic colour’ but is caused by atmospheric effects, he writes, ‘This may be seen, as I myself have seen it, by anyone who goes to the top of Monboso.’ Opinions differ as to which mountain ‘Monboso’ is. The probable location is Monte Rosa, which seems also to have been known as Monte Boso (from the Latin buscus, wooded), particularly on its southern side, which is the side Leonardo would have climbed.49 The highest peaks of Monte Rosa (15,200 ft) were not conquered till 1801, but Leonardo is probably not claiming to have been at the very top. He was there in July, he tells us, but the year is not specified. Even in July, he notes laconically, the ice was ‘considerable’.

  The all-important phrase in this note – the phrase implicit in all these notes concerning his Alpine excursions – is this: ‘I myself have seen it. He would understand the words of the great German physician Paracelsus, written in the 1530s: ‘He who wishes to explore Nature must tread her books with his feet. Writing is learned from letters but Nature from land to land. One land, one page. Thus is the Codex Naturae, thus must its pages be turned.’50

  CASTING THE HORSE

  Here is a story to gladden every library-mole’s heart. In February 1967 a specialist in early Spanish literature, Dr Jules Piccus of the University of Massachusetts, was in the Biblioteca Nacional in Madrid, looking for manuscripts of medieval ballads or cancioneros, when he came upon two stout volumes bound in red morocco leather, measuring about 9 by 5 inches. He was astonished to find that they contained a collection of drawings and writings described on the title-page, in a Spanish hand of the eighteenth century, as ‘Tractados de fortificación, mecanica y geometra’ by ‘Leonardo da Vinci pintor famoso’. That the library had once contained these volumes was known to a handful of scholars – they are mentioned in a couple of early inventories – but they were thought to have been lost or stolen. As it now turned out they had merely been mislaid, as can happen in great and aged libraries: they had disappeared into the miasma of the stacks.51

  The earliest of the various tractados, or treatises, bound together in the two volumes is a small notebook of seventeen folios which forms the last section of Madrid Codex II. It contains detailed notes and instructions for the casting of the Sforza Horse. Two dated pages give its approximate chronology. Leonardo began it on 17 May 1491, on which date he wrote, ‘Here a record shall be kept of everything relating to the bronze horse now under construction.’ On another page is the date 20 December 1493, recording his decision to cast the horse on its side rather than upside down.52

  The practical construction of the Sforza Horse consisted of three distinct phases: the making of the full-scale model in clay; the creation of the mould or form, a wax impression of the model sandwiched between two refractory layers pinned together by an iron framework; and the final casting of the statue in bronze, using the ‘lost-wax’ process in which the wax impression is melted away and molten bronze is poured into the emptied cavity between the refractory layers.53 As we have seen, Leonardo’s conception of the statue had evolved from the grandiose but impractical idea of the rearing horse to the more conventional trotting or prancing horse. His enthusiastic response to the Regisole in June 1490 may mark the transition, though it seems that the earlier idea lingered in his mind, for in one of his drawings of a mould the horse is shown rearing. But most of the casting diagrams, including those in the Madrid notebook, show it trotting, and it is pretty certain this was the final form of the sculpture in Leonardo’s mind. A sketch of a trotting horse à la Regisole has notes which sound almost like a sculptor’s mantra:

  Simple and composed movement.

  Simple and composed force.54

  Armatured piece-mould of the head of the Sforza Horse, c. 1492.

  He was working intensively on the construction of the mould in 1492. A sheet at Windsor has a sketch of the mould in two parts, and designs for the construction of pulleys and cog-wheeled mechanisms, presumably for hoisting the mould.55 The Madrid notebook has technical recipes:

  Composition of the inside of the mould

  Mix coarse river sand, ashes, ground brick, egg-white and vinegar together with your earth – but test it first.

  Soaking the inside of the mould

  As soon as you have re-baked the mould, soak it while still warm with Greek pitch, or linseed oil, or turpentine or tallow. Try each of them out and use whichever is best.

  Study of diminishing power in a spring, from Madrid Codex I.

  A meticulous red-chalk drawing shows the outer mould for the head and neck of the horse, held in place by the interlocking framework or ‘armature’ of wood and iron.56

  In his Life of the Florentine architect Giuliano da Sangallo, Vasari says that Sangallo discussed the casting of the Horse with Leonardo, ‘disputing the impossibility’. Documents show that Sangallo was indeed in Milan in October 1492.57 The ‘impossibility’ would refer to Leonardo’s decision – against traditional practice – to try to cast the horse as a single piece. Vasari thought (wrongly) that this was the reason for the non-completion of the statue: ‘He carried the work forward on such a scale that it was impossible to finish it… It was so large that it proved an insoluble problem to cast it in one piece.’

  Behind these technical notes and scribbled diagrams lie scenes of titanic industrial activity – the Corte Vecchia as a Vulcan’s smithy: furnaces, kiln-pits, hoists and derricks, a scene reminiscent of that drawing of an artillery-foundry. One has to bear in mind the mountainous scale of the statue: it was ‘colossal’, in the words of Paolo Giovio, who probably saw the clay model as a boy. A measurement in the Madrid notebook shows that the Horse measured 12 braccia from hoof to head – that is, about 24 feet: the height of four tall men. The length between the hind fetlock and the raised foreleg would be about the same. Leonardo’s Horse was thus something like three times lifesize. The quantity of bronze set aside for the final casting was 100 meira – about 75 tons.58

  The clay model of the Horse was exhibited in late 1493, on the occasion of the marriage of Ludovico’s niece Bianca to the Holy Roman Em
peror, Maximilian of Habsburg. The wedding was celebrated in Milan, by proxy, on 30 November. A clutch of celebratory poems was issued, all of them mentioning the Horse as part of their lauding of Ludovico. Baldassare Taccone writes:

  Vedi che in Corte fa far di metallo

  Per memoria del padre un gran colosso:

  I’ credo fermamente e senza fallo

  Che Gretia e Roma mai vide el piu grosso.

  Guarde pur come è bello quel cavallo:

  Leonardo Vinci a farlo sol s’è mosso…

  [See in the Corte how he [Ludovico] is having a great colossus made out of metal in memory of his father. I am certain that neither Greece nor Rome ever saw anything bigger. See how beautiful this horse is: Leonardo da Vinci alone has created it.]

  As the bronze horse was never actually cast, Taccone must be referring to the model. Another rimester, Lancino Curzio, finds the horse so lifelike that he imagines it addressing some lines to an astonished observer.59 Vasari: ‘Those who saw the great clay model that Leonardo made considered that they had never seen a finer or more magnificent piece of work.’

  By then Leonardo was already thinking about the casting process, for on 20 December 1493 he writes, ‘I have decided that the horse should be cast without its tail, on its side, because if I were to cast it upside down the water would be only one braccio away, and… as the mould must stay underground for several hours, the head one braccio from the water would be affected by damp, and the cast would not take.’60 These considerations refer to the pit in which the casting was to be done. To cast the horse upside down would require a pit 12 braccia deep, which would bring the head too close to the shallow water-table of the Lombard plain.

  The creation of the great clay horse in 1492–3 is only a part of Leonardo’s work as an engineer and mechanician, as is shown by the magnificent drawings in Madrid Codex I, begun on 1 January 1493 and worked at over a period of seven or eight years. On the cover-sheet Leonardo gives the notebook the title Libro di quantita e potentia (Book of Quantity and Force). It may also be the ‘book on mechanical elements’ and the ‘technical book on physics’ which he refers to elsewhere and which are otherwise unknown.61 It is a marvellous manual of ingegni, a cornucopia of custom-made industrial devices – there are textile-machines and grain-mills and protypical windmills, and a spinning-wheel incorporating an automatic yarn-twisting mechanism, and various lifting-devices, including crane-hooks designed to disengage when the load touches the ground. But it is not primarily a book of inventions. Rather than showing complete working machines, it concentrates on the basic mechanical principles and movements involved. The remit is systematic and practical, geared towards the actuality of the assembly-line. Leonardo is quite literally getting down to nuts and bolts, not to mention chain-drives and belt-drives, universal joints and knuckle-joints, roller-bearings and disc-bearings, bi-directional screw-threads and epicycloidal gear-wheels. It is a boffin’s paradise, as is conveyed infectiously by the first editor of the codices, Ladislaus Reti.

  Leonardo’s assistants are of interest here. The German Giulio (or Julius), who entered Leonardo’s service in 1493, is mentioned in a note about disc-bearings supporting a horizontal axle: ‘Giulio says he has seen two such wheels in Germany and they became worn around the spindle.’62 And the metallurgist Tommaso Masin’, or Zoroastro, was also an important assistant in these researches, as he no doubt was in the casting of the Horse. A note in one of the Forster notebooks tells us that ‘Maestro Tommaso came back’ in September 1492; he may have travelled up from Florence with Giuliano da Sangallo, with whom Leonardo was conversing the following month, ‘disputing the impossibility’ of the Horse. To Tommaso we might attribute the particular alloy of metals specified by Leonardo for the moving parts of a two-piece bearing-block. The material is essentially an ‘antifriction alloy’, predating by centuries the substance patented by the American inventor Isaac Babbitt in 1839.63

  Among the diagrams of Madrid I are drawings showing the moving parts of one of Leonardo’s most fascinating creations – an automaton or robot in the form of a knight in armour. Mechanisms featuring gears with alterable teeth, and ingeniously compact motors regulated by a spindle, have been interpreted as part of the robot’s ‘programmable carriage’. This automatic knight was capable of bending its legs, moving its arms and hands, and turning its head. Its mouth opened, and an automatic drum-roll within the mechanism enabled it to ‘talk’. There are sketches of the head and neck of this cavaliere meccanica in the Forster notebooks. It was exhibited in Milan in about 1495.64 These automata become fairly common in popular and courtly feste in the sixteenth century, but Leonardo’s seems to be one of the earliest. In fact his interest in automated movement goes back to his Florentine years. There is a sheet of technical drawings dating from the late 1470s which shows a wheeled platform powered by springs and controlled by a pinion-wheel. This was probably for use in Florentine pageants: it could carry some statue or carnivalesque effigy short distances. A reconstruction of it – dubbed in the press ‘Leonardo’s car’ – was unveiled at Florence’s History of Science Museum in April 2004. This earlier interest can be connected to one of Verrocchio’s most popular creations – the putto which struck the hour on the clock at the Mercato Vecchio.65 The principles of horology are an important background for Leonardo’s automata, though according to Mark Rosheim, a NASA scientist who has reconstructed a working model of the robot-knight, Leonardo was moving far beyond the limitations of clockwork: his programmed carriage for automata is nothing less than ‘the first known example in the story of civilization of the programmable analogue computer’.66

  The knight is a wonderful blend of Leonardian enthusiasms – mechanics, anatomy, sculpture, theatre. He would create other such marvels, among them the mechanical lion which, in 1515, astonished King François I when it opened up to reveal a bunch of French lilies. Lomazzo says of this creature, ‘it moved along by the power of its wheels’, which for a moment gives an impression that he is explaining how it worked.67

  ‘CATERINA CAME…’

  In the summer of 1493 a woman called Caterina arrived at the Corte Vecchia. She was still there early the following year, when she is mentioned in the household accounts. Then, probably in 1495, come the expenses of her funeral, also recorded by Leonardo.68 We don’t know who she was, but it is hard to resist the possibility that she was his mother, who in 1493 would have been in her mid-sixties, and since about 1490 a widow.

  Leonardo records her arrival as follows:

  On the 16th day of July.

  Caterina came on the 16th day

  Of July 1493.

  One notes immediately the tic of repetition which is also found in the memorandum of his father’s death a decade later. In the latter case it was interpreted by Freud as the psychological mechanism he calls ‘perseveration’, where deep emotions are sublimated or diverted into fussy repetitive action and ‘indifferent detail’. ‘The psychoanalyst’, he writes, apropos Leonardo’s note on his father’s death, ‘has learned long ago that such cases of forgetting or repetition are significant, and that it is the “distraction” which allows impulses that are otherwise hidden to be revealed.’ This ‘perseveration’ is thus kin to the more famous ‘Freudian slip’, in which linguistic errors reveal a suppressed text.69

  The account of Caterina’s funeral is precisely a bland piece of accountancy. Here again one might discern that diversionary focus on ‘indifferent detail’:

  Funeral expenses for Caterina

  3 pounds of wax

  27 soldi

  For the bier

  8 s

  A pall over the bier

  12 s

  For carrying and placing the cross

  4 s

  For carrying the coffin

  8 s

  For 4 priests and 4 clerks

  20 s

  Bell, book and sponge

  2 s

  For the gravediggers

  16 s

  To the elder [an
tiano]

  8 s

  For the licence from the authorities

  1 s

  [Subtotal] 106 s

  The doctor

  5 s

  Sugar and candles

  12 s

  [Total]123 s

  This is not an extravagant funeral. The costs amount to a little over 6 lire – he would spend four times that amount on a fancy silver cloak for Salai in 1497. The quantity of wax for tapers is 3 pounds; for his own funeral he would stipulate 40 pounds (10 pounds of wax ‘in thick tapers’ to be placed in each of four churches).

  We cannot be certain that ‘Caterina’ was his mother, but if she wasn’t who was she? Elsewhere in the notebooks those who come into his household to stay or live with him are all male: assistants, apprentices, servants. It was legally impossible for Caterina to have been an apprentice, and unlikely that she was a skilled assistant of some sort. The only plausible interpretation would be that she was a servant: a cook and housekeeper, let us say – much like the Mathurine or Maturina who later served him in France. These are the alternatives: that the Caterina of the Milanese notebooks was an otherwise unknown woman who served as his housekeeper for a couple of years or that she was his widowed mother, reunited with him in her last years, accommodated amid the trappings of his success, comforted by him on her deathbed in 1495, at the age of about sixty-eight. Either is intrinsically possible: one must make or refuse the leap of faith. Some have thought that the modesty of the funeral argues against her being his mother. But Caterina was essentially, in style and manner, a Tuscan contadina, and what one guesses of her character does not lead us to think she would wish to pretend otherwise. She is lined by the tough years of work on the little farm at Campo Zeppi. These exequies, simply but properly done, would be right for her.